BEIRUT — Syrian Kurdish officials say thousands of members of a religious minority group have fled across the border from Iraq after coming under attack by Islamic extremists.

Ekrem Hasso and Juan Mohammad told The Associated Press on Saturday that the Yazidis fled after Kurdish fighters were able to open a safe passage into Syria following clashes with the Islamic State group.

Their comments came as the U.S. launched airdrops to aid thousands of Yazidis who have been trapped on a mountaintop for days by the militants.

The extremists have captured hundreds of Yazidi women, according to an Iraqi official, while thousands of other civilians have fled in fear as the militants seized a string of northern Iraqi towns and villages in recent days.